Subjects are eligible for this study if they have been on greater than or equal to 2 ART for greater than or equal to 4 months prior to randomization, with no change in the type of ART received during this 4-month period of time. For subjects who receive only 2 ART, at least one of these two medications should be a protease inhibitor (PI). Subjects are not eligible if ART is discontinued for a cumulative period of 7 or more days during the 4 months prior to randomization.